A week before Pennsylvania's Democratic primary... John McCain traveled to Pittsburgh to remind everyone how different his economic agenda would be from theirs.
In a speech that day, he said he would abolish the dreaded alternative minimum tax. He said he would also allow companies to write off spending on new equipment more quickly than they now could, effectively reducing their taxes. Most ambitiously, he vowed to set up a simpler income tax system, one that anyone could voluntarily use instead of the current tangle. In the months since then, Mr. McCain has repeated these vows.
Fast forward to last week, when a Washington research group called the Tax Policy Center set out to estimate the budgetary effects of Mr. McCain's and Mr. Obama's plans, after having talked with the campaigns about the details. Almost immediately, the center's report became the yardstick that journalists and bloggers used.
To anyone who has been following the campaign closely, however, there were some strange things in the report's summary. The alternative minimum tax? Mr. McCain apparently no longer wants to abolish it. The write-off for corporate equipment? It exists for a few years, but then it disappears. The simple new tax system? Gone.
...Here, then, are three questions that I hope Mr. McCain will answer soon:
No. 1: Are you really going to eliminate the alternative minimum tax?
...Mr. McCain, in speeches, is perfectly clear about what he wants to do: "Abolish the A.M.T.," as he said to a conservative group. Yet his campaign told the Tax Policy Center that "Senator McCain does not plan to repeal the individual A.M.T."
...In the fine print of his plan, he doesn't abolish the tax. Instead, he "patches" it, so that it would continue to apply to roughly the same number of households as it did last year — about one out of every 30. (Mr. Obama's A.M.T. proposal isn't so different.) The trick is that no one would actually pay the tax under the McCain plan. As Douglas Holtz-Eakin, a campaign adviser, explained to me, anyone hit by the A.M.T. could opt into Mr. McCain's voluntary, simplified tax system, where their taxes would be lower.
Of course, no matter what it's called, an effective elimination of the A.M.T. will cost the government a lot of money — about $60 billion a year. As a point of comparison, the entire deficit is projected to be $300 billion a year during the next president's first term.
No. 2: Are you serious about tax simplification?
If I told you that you could choose between two different set of tax rules, I'm guessing that you would pick the one that required you to pay less in taxes. Such a system, then, would have to cost the Treasury a good bit of cash. It's inherent.
Fred Thompson, during his brief campaign, proposed a system along these lines, and the Tax Policy Center estimated that it would have increased the deficit by some $600 billion a year. "It would be the largest tax cut ever, by a large margin," said the center's director, Len Burman (who, I should add, has been careful to note what his calculations do and do not include).
The McCain campaign says its proposal won't be the same as Mr. Thompson's, but the two certainly are similar. Mr. Holtz-Eakin is responsible for coming up with the details, he said, and he is under orders "to make it revenue neutral." That means the plan will pay for itself — that it will include tax increases to offset the reductions. When Mr. McCain describes those increases, you'll know he's serious about tax simplification.
No. 3: Are you going to use gimmicks to make your numbers add up?
In 2001, President Bush signed a 10-year tax cut with a novel feature. In the final years of the cut — 2009 through 2011 — it began disappearing, making the cost look smaller than it otherwise would have. Now that those final years have arrived, however, Mr. Bush argues that Congress should restore the tax cut.
Mr. McCain agrees... Yet his campaign agenda includes one of these same sunset provisions (which wasn't apparent until the Tax Policy Center analysis came out). The new rule on corporate deductions for equipment lasts only until 2013, when the old rule — with its higher taxes — returns. This gimmick, obviously, helps reduces the proposal's apparent cost.